1. Field of the Invention
The present invention relates to coating compositions, methods of coating substrates with the coating compositions, and substrates coated with the coating compositions.
2. Description of Related Art
Current art is primarily based on epoxy resin technology cured with amino resins and phenolics. Coating compositions formed from bisphenol A based epoxy resins and polyvinyl chloride have been used to coat packaging and containers for foods and beverages. However, there is a desire among some consumers and brand owners for coating compositions free, or substantially free, of bisphenol A and polyvinyl chloride for packaging and containers for food and beverages.
Commonly-owned patent publication WO 2010/100122 discloses a coating composition comprising a hydroxyl functional oil polyol prepared by a method comprising reacting an epoxidized vegetable oil with a hydroxyl functional material in the presence of an acid catalyst. Commonly-owned patent publication WO 2010/100121 discloses a coating composition comprising a hydroxyl functional oil polyol acrylic graft copolymer prepared by a method comprising reacting an epoxidized vegetable oil with a hydroxyl functional material in the presence of an acid catalyst to form a hydroxyl functional oil polyol, reacting the hydroxyl functional oil polyol with an ethylenically unsaturated monomer component in the presence of an initiator to form a hydroxyl functional oil polyol acrylic graft copolymer, and crosslinking the hydroxyl functional oil polyol acrylic graft copolymer with a crosslinker to form the coating composition. However, some oil polyol technology does not have intrinsically good flexibility and can benefit from further modification when the material is to be used as a packaging coating composition.
UK patent application GB 2218704 disclosed an aluminum or tinned-steel can for carbonated beverages protected by an aqueous coating formulation of a polyethylene-maleic acid copolymer. The aqueous solution as applied preferably contains from 5-20% by weight solids which is too low for beverage can-ends applications. Also, the coating applied to the substrate was heat-cured at 200° C. for 10 minutes which is too long and not applicable for can-ends applications.
There is a desire to produce packaging coating compositions that do not contain bisphenol A or polyvinyl chloride or are substantially free of the same. The coating compositions of the invention can be used, inter alia, as packaging coatings for food and beverage packaging and containers. They can be formulated to provide higher solids for application and improved toughness, corrosion resistance, flexibility, blush resistance and retort resistance compared to some commercial coating compositions.